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This year, three graduate students in our group have won outside fellowships supporting their research into short-range correlations and hadron-structure modification in the nuclear medium. That three different agencies all elected to fund our students’ proposals speaks both to the talent and productivity of our students as well as the importance of their work.

Erin Seroka wins a 2022-23 Jefferson Lab JSA Graduate Fellowship

Erin was named one of the winners of a 2022-23 Jefferson Lab JSA Graduate Fellowship, supporting her work investigating the isospin structure of short range correlations. Erin hopes to show that the observed rise in prevalence of proton-proton short-range correlations with missing momentum is accompanied by a decrease in the prevalence of proton-neutron short range correlations. Her analysis of data from the CLAS12 Short-Range Correlations Experiment has required a huge investment of time and effort into understanding the performance of the CLAS12 Central Neutron Detector, and has made her one of the collaboration experts on that detector.

Sara Ratliff wins a 2022-23 Center for Nuclear Femtography Graduate Fellowship

Sara has won a fellowship from the Center for Nuclear Femtography supporting her work researching the motion of quarks inside bound protons and neutrons. Sara’s research uses the novel technique of “spectator recoil tagging,” using the simultaneous detection of a neutron that was merely a spectator to a nearby violent deep inelastic scattering collision to learn about the initial state of the struck nucleus or nucleon. Sara uses the CLAS12 Backward Angle Neutron Detector (BAND) to detect neutrons and has become a critical member of BAND team, working understand the efficiency and performance of the detector.

Phoebe Sharp wins a 2022-23 US Dept. of Energy, Office of Science Graduate Fellowship

Phoebe was named one of the winners of the 2022-23 US. Department of Energy Office of Science Graduate Research Fellowships, supporting her proposal to learn about short range correlations using the novel technique of rho meson photo-production. Instead of using the conventional method of quasi-elastic electron scattering to break up a short-range correlated nucleon-nucleon pair, Phoebe’s thesis experiment used a high energy photon beam. Phoebe is investigating signatures of pair break-up through the detection of a highly unstable rho-0 meson. Short-range correlations have never been observed in photon-induced reactions, and Phoebe hopes not only to break new ground in detection, but also confirm that previously seen properties of short-range correlations are in fact “reaction independent.”

GW Today featured one of my undergrad advisees, Gabe Grauvogel, in a news article, and talks a little bit about the kind of exciting research in nuclear physics that undergraduates can contribute to. This is a great credit to Gabe’s hard work and enthusiasm for physics.

The U.S. Dept. of Energy’s Office of Science has featured our recent paper, “Probing the core of the strong nuclear interaction” (Nature 578, pp. 540–544, 2020) as one of its Nuclear Physics Science Highlights. The highlight, titled “Researchers Overcome the Space between Protons and Neutrons to Study the Heart of Matter” recognizes this work as one of the most significant recent achievements from the nuclear physics research sponsored by the Dept. of Energy (DOE). In addition to supporting the research, the experimental data in this paper were collected at the Thomas Jefferson National Accelerator Facility (JLab), a DOE-operated facility.

The group was well-represented at this year’s APS Division of Nuclear Physics Fall Meeting, with Phoebe, Sara, Tyler, Axel, and group alum Holly all giving talks about their latest research results. But for CoVID, the meeting would have been held in New Orleans, but it seamlessly transitioned to Zoom.

In her first APS talk, Sara presented her work on the upcoming LAD experiment, in which a measurement of deep inelastic electron-scattering on neutrons deuterium—with the crucial addition of a “tag” on the spectator proton—can help test the connection between the EMC Effect and short-range correlated nucleons. Sara presented her studies of simulated backgrounds, which will help optimize electron spectrometer settings. In the same session, Tyler also presented the latest analysis of the complementary BAND experiment.

In her first APS talk, Phoebe presented the upcoming SRC@GlueX Experiment in Jefferson Lab Hall D, in which short-range correlations will be probed using a high-energy photon beam. She showed her latest simulation studies helping to plan and optimize the run, which will begin in August, 2021.

We’re all looking forward to in-person meetings in the future, but until then, stay safe, wear a mask, keep social distance!

This past week, the Physics Department Colloquium Series resumed for the fall semester, though with Covid restrictions it will be an online affair. Tyler was the opening speaker, and talked about the connections between his PhD work—investigating the structure of the neutron by scattering electrons from helium-3 and tritium—and his current work—investigating how proton and neutron structure can change within nuclei. The two topics are inexorably linked. Since there is no way to make a free neutron target, one can only study neutrons within nuclei. But at the same time, one needs to understand the structure of the neutron to study nuclei. Tyler’s work on the BAND experiment and (upcoming) LAD experiment will hopefully give us a clear picture of the neutron’s (and proton’s) structure inside nuclei.

 

Tyler delivered this week’s MIT Laboratory for Nuclear Science Colloquium, speaking on his work with the MARATHON Experiment, as well as a giving a preview of results on extracting free neutron structure from deep inelastic scattering from nuclei. These will appear in PRL soon, stay tuned!

The BAND Detector is seeing neutrons!

The site is up and running. It’s just basic info at the moment, but in the coming weeks and months I hope to add information about the group, our projects, and our latest results. Stay tuned.

-Axel